Fixing PostgreSQL support

[danrot]

This branch is activating the build for PostgreSQL, which is currently failing. @carltongibson will create some Pull Requests targeted at this branch to fix this.

tasks:

• test coverage
• gather feedback for my changes
• submit changes to the documentation

informations:

q	a
Fixed tickets	fixes #53
BC breaks	hopefully none
Documentation PR	none

[carltongibson]

Update:

Of the originally failing bundles, we're about half way there. #1720, #1725, #1726 fixes Categories, Contacts and Tags respectively. (@danrot: please review at your leisure.)

I have to pause until next week now but I will continue with MediaBundle. The queries here are more complex but, it is exhibiting the same semi-random failures as I found in #1725.

Here's one run:

.............F.....F..................................F.F......  63 / 108 ( 58%)
.............................................

And here's another one straight after:

.................................................F..FF.F.F.....  63 / 108 ( 58%)
.............................................

Same tests. Different failures. :-)

Again it'll just be a case of providing Postgres with the correct ordering. (There is an $orderBy parameter being passed around so I need to see exactly what's happening to that but I'm assuming it'll be a single change in the end.)

Having got this far without incident I'm optimistic that ResourcesBundle and SecurityBundle will prove relatively easy to resolve as well. (I haven't yet looked)

[danrot]

@carltongibson The progress already looks quite good, there aren't too many failing tests left. However, it would be good if we don't wait too long on finishing this, I've already seen a new feature failing some tests again 😕

[carltongibson]

@danrot Yeah — I didn't think I was far off. IIRC there were remaining ordering issues — with intermittent failures and that was about it.

(I thought ordering the relations may be all that's needed there — but didn't get to check that.)

Will say more in Feb! Ping me on anything relevant so I can keep up.

[danrot]

Replaced by #2703